Mainz 2017 – scientific programme
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MS: Fachverband Massenspektrometrie
MS 2: Precision Mass Spectrometry and Fundamental Applications II
MS 2.6: Talk
Monday, March 6, 2017, 18:30–18:45, RW 2
Peak shape analysis of high resolution Multiple-Reflection Time-of-Fight Mass Spectrometer (MR-TOF-MS) data — •Sivaji Purushothaman and The FRS ION Catcher Collaboration — GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany
At the FRS Ion Cather setup, GSI, Darmstadt, the in-flight produced and separated radioactive isotopes are thermalized in a gas stopping cell and delivered to a Multiple-Reflection Time-of-Flight Mass Spectrometer (MR-TOF-MS). Due to the universal production in combination with the fast and high precision, high accuracy mass measurement capability, the FRS ion catcher setup is an ideal tool for studies of long-lived isomers (life times greater than a few milliseconds). However, the detected peak shape in MR-TOF-MS often shows symmetric and asymmetric deviations from a Gaussian form as a result of several processes, which cannot be disentangled. In the case of overlapping peaks, the peak position and the area will be influenced by the underlying tails from the neighboring peaks. This is critical for many high precision measurements, for example to deduce isomeric-to-ground state ratios and to determine the excitation energy of an isomer. A new probability distribution function called hyper-Exponentially Modified Gaussian (hyper-EMG), which can model a Gaussian distribution modified with multiple exponential tails at either one or both edges is presented. The application of the new peak shape model in MR-TOF-MS data analysis is demonstrated with the isomers observed from projectile (211Po) and fissions (133I) fragmentation of 238U.